GIA GEMOLOGIST ARTICLE

The Definitive Aquamarine Buying Guide

Everything you need to know about Aquamarine Gemstones. Learn all about this beautiful, rare gemstone. Learn about its properties, how to judge quality, pricing, how it is mined, where it comes from and how to spot imitations.

...
Antony Zagoritis

GIA Graduate Gemologist
ICA Ambassador to Kenya



Aquamarine, the serene blue-to-green-blue variety of the mineral beryl, has long been cherished for its calming color and ocean-like beauty. Its name comes from the Latin aqua marina, meaning “water of the sea.” Revered since ancient times as a gem of sailors, clarity, and harmony, aquamarine remains one of the most popular colored gemstones in the world.





MAJOR SOURCES OF AQUAMARINE IN THE WORLD


  • Aquamarine is mined worldwide, with some locations producing highly prized stones:

Aquamarine Major Sources in the world.jpg

      1. Brazil – The leading source; Minas Gerais yields large, gem-quality crystals.

      2. Madagascar – Produces high-clarity, pastel blue Aquamarines.

        Nigeria & Mozambique – Known for intense blue stones.

      3. Russia (Ural Mountains, Siberia) – Historic source.


QUALITY FACTORS


  • Like most colored gemstones, Aquamarine value is determined by the Four Cs - Color, Clarity, Cut and Carat Weight.
Let's look at Color first, as it is the most important metric.

  • Aquamarine Gemstone Color Qualities.jpg


  • The GIA (Gemological Institute of America) has one of the most scientific of the colored stone grading systems. It breaks color 
    down into 3 components - Hue, Tone and Saturation. The chart below shows how these work:


Aquamarine Tone and Saturation.jpg


Basically, "Color is King" when it comes to colored gemstones and Aquamarine is no exception. Value is directly linked to the color quality.


Next, let's take a look at the second most important of the 4C's - Clarity. 

Clarity refers to how clean an Aquamarine is - how free of inclusions. The cleaner it is the more rare and valuable. The GIA grades clarity much like it does in its Diamond grading system. The principal difference is that in order to ensure gemstones are graded fairly it has grouped different gem types into "Types" depending on their propensity to contain inclusions. Aquamarine is grouped in the Type 1 category which  is the highest group, meaning that it is graded the most strictly. The chart below gives you an idea of how each grade might look : 


Aquamarine Clarity Grades.jpg

Next, we will look at cut. Unlike Diamonds, where cut grading has taken on a scientific mantle, largely because much of Diamond's beauty derives from its cut, colored stones are not held to the same standard. This is not to say that cut quality is not important, it is.  The key factors to look out for are Crown Angle and height, Pavilion angles and depth, symmetry and lastly faceting.

First, let's examine Pavilion angles and depth. Aquamarine has a high critical angle. What that means is that the angles used on the pavilion are very important to avoid a "window". A window is where there is no internal reflection due to light not bouncing within the stone. The chief cause of this is usually either a shallow pavilion or a deep bulged pavilion as shown below.


Bulged pavilion.jpg 
Illustration showing how a deep and bulged (heavy) pavilion (back) results in an ugly window effect in an Aquamarine. Note how the image on the far right shows a dead area in the center of the stone - that is a window caused by light leakage.

The diagram below shows why this phenomenon occurs and how a well cut Aquamarine would reflect light

Light theory in Aquamarine gemstone cut.jpg

  • So, in conclusion, you want to avoid Aquamarines with heavy or bulged pavilions, high crown angles and bad symmetry. Aim for a stone with nice, sharp angles and no window with good internal reflection and brilliance.



  • PHYSICAL AND OPTICAL PROPERTIES


    • Hardness (Mohs): 7.5–8 (durable for jewelry)

    • Color Origin: Aquamarine’s blue color comes primarily from trace amounts of iron (Fe²? and Fe³?) in its crystal structure.

    • Crystal System: Hexagonal

    • Refractive Index (RI): 1.577–1.583

    • Specific Gravity: 2.68–2.74
    •  

TREATMENTS


  • Aquamarine typically doesn't undergo treatments except for heat. Aquamarines with a strong greenish undertone can be heated to remove the yellow component in its color, leaving a more pure blue. This is stable and permanent and is considered acceptable in the trade. Unheated stones do command a premium in the market, especially if they have good color.

  • Aquamarine heating.jpg

It is important to note that heating Aquamarine does not improve its saturation at all, much like heating Tanzanite. The only effect it has is to remove or diminish the yellow component, making the stone less greenish.

Aquamarine before and after heating.jpg


The photo above shows Aquamarine crystals before and after heating. The left hand photo shows the stones before heating, note the greenish component. The right hand photo shows the Aquamarines after heating at 400 degrees centigrade for one hour. The yellow component has been removed leaving a purer blue hue.




USES IN JEWELRY


  • Popular Settings: Rings, pendants, earrings, and bracelets.

  • Metal Pairings: White gold and platinum highlight aquamarine’s cool tones, while yellow gold gives a warm contrast.

  • Fashion Trend: Favored for statement pieces due to large crystal sizes.

Aquamarine Jewelry at The Rare Gemstone Company.jpg


  • CARE AND MAINTENANCE

  • Durability: Hard enough for everyday wear but can be scratched by harder materials (like diamond or sapphire).

  • Cleaning:

  • Safe with warm soapy water and a soft brush.

  • Ultrasonic cleaners are usually safe but avoid if inclusions or fractures are present.

  • Avoid exposure to prolonged heat or harsh chemicals.

  • Storage: Store separately to prevent scratches from harder gemstones.


  • Aquamarine is a gemstone of timeless beauty and enduring symbolism, offering a balance of affordability, durability, and elegance. Whether in antique royal jewels or contemporary designer pieces, its oceanic blues continue to captivate gemstone lovers around the world.


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ABOUT THE AUTHOR Antony Zagoritis, Bsc, GG

Antony completed his GG (Graduate Gemologist) in 1998 at the Gemological Institute of America in California after a degree a Business at the University of Bath, in England. He has extensive experience in the colored gemstone trade with over 20 years buying rough at the source. He is currently the Ambassador to Kenya for the ICA (International Colored Gemstone Association) in New York which is the worldwide body for colored gemstones.

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